1. Field of the Invention
The present invention relates to a magnetic recording and reproducing apparatus of a type wherein magnetic recording and reproducing are conducted by a magnetic head disposed on the surface of a magnetic disk of a rigid substrate while the disk is rotated at a high speed. Particularly, it relates to such apparatus wherein recording and reproducing are conducted by a magnetic head which is caused to fly at at least the outermost track of the magnetic disk and is caused to be in contact with the surface of the magnetic disk at at least the innermost track, whereby the durability of the magnetic disk and the magnetic head can be improved, the spacing loss can be reduced, and high density recording is made possible.
As is well known, in a magnetic recording and reproducing apparatus of this type, a hard magnetic disk comprising a rigid substrate made of aluminum and a thin magnetic layer formed thereon by a method such as a fine magnetic powder coating method, a plating method or a sputtering method, is rotated at a high speed (e.g. 3600 rpm) so as to produce a dynamic pressure between the magnetic disk and a flying magnetic head so that the magnetic head is lifted and floats with a certain flying height by a fine air bearing, while the magnetic recording and reading-are conducted.
In order to accomplish high density magnetic recording with a magnetic recording and reproducing apparatus of this type, it is necessary to minimize the flying height of the magnetic head and to reduce the spacing loss.
As a conventional technique to obtain high density magnetic recording by reducing a flying height of the magnetic head, there is known one as disclosed in, for instance, Japanese Unexamined Patent Publication No. 287002/1986. In the known technique, recording and reproducing are conducted by bringing magnetic head into contact in substantial meaning with a magnetic disk with a magnetic recording layer formed on a rigid substrate while the head and the disk are relatively moved at a high speed.
In accordance with the above-mentioned conventional technique, the spacing loss can be made small and excellent recording and reproducing characteristics and recording density characteristics are obtainable. However, the conventional technique adapted to perform recording and reproducing by bringing the magnetic head substantially in contact with the surface of the magnetic disk has a problem such as a damage to the magnetic disk or a head crash and the durability tends to be low. Especially, such risk is large when the surface of the magnetic disk is composed of a metal or alloy such as Co-Cr or the like.
The present invention is to eliminate the above-mentioned problem and is to provide a magnetic recording and reproducing apparatus of a type wherein a magnetic disk having a magnetic recording layer formed on a rigid substrate is rotated at a high speed and magnetic recording and reproduction are conducted by the magnetic head disposed on the surface of the disk, the magnetic recording and reproducing apparatus being characterized in that the magnetic recording and reproducing are conducted by the magnetic head which is caused to fly from the magnetic disk at at least an area of the outermost cylinder of the magnetic disk and is caused to be substantially in contact with the surface of magnetic disk at at least an innermost cylinder of the magnetic disk.